[core, hle, video_core, memory] Improve multi-process, display layers, dynamic shader cache and rework overlay (#4238)

- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md)
- [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.

-------------------

- Dynamic shader cache reloading capability for qlaunch
- Multi-process improvements (thanks to @frank1734), instead of just using the main application we now respect caller process (also did it for HID devices while I was at it)
- Layer stack masks & shared buffer screenshot for video core, added different masks (screenshot, recording, etc.) this was discovered as an issue due to how in qlaunch the transition was not right between applications. May not be perfect but also fixes screenshots while using qlaunch
- Reworked overlay display management (input and visibility) - instead of random numbers as I've previously did, I decided to add an AppletZIndex enum for better readability. Also split capability of input by touch and gamepad.
- etc.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4238
Reviewed-by: Samuel <lizzie@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

2 files changed, 65 insertions, 4 deletions

diff --git a/src/android/app/src/main/jni/native.cpp b/src/android/app/src/main/jni/native.cpp
index 4d0c39f5c7..e8e9f0a14b 100644
--- a/src/android/app/src/main/jni/native.cpp
+++ b/src/android/app/src/main/jni/native.cpp
@@ -76,6 +76,7 @@ extern "C" {
 #include "core/frontend/applets/software_keyboard.h"
 #include "core/frontend/applets/web_browser.h"
 #include "common/android/applets/web_browser.h"
+#include "core/file_sys/common_funcs.h"
 #include "core/hle/service/am/applet_manager.h"
 #include "core/hle/service/am/frontend/applets.h"
 #include "core/hle/service/filesystem/filesystem.h"
@@ -311,11 +312,23 @@ Core::SystemResultStatus EmulationSession::InitializeEmulation(const std::string
     ConfigureFilesystemProvider(filepath);
 
     // Load the ROM.
+    const u64 previous_program_id =
+        program_index != 0 && m_next_program_id.load() >
+                                  static_cast<u64>(Service::AM::AppletProgramId::MaxProgramId)
+            ? m_next_program_id.load()
+            : 0;
+
     Service::AM::FrontendAppletParameters params{
+        .program_id = previous_program_id,
         .applet_id = static_cast<Service::AM::AppletId>(m_applet_id),
         .launch_type = frontend_initiated ? Service::AM::LaunchType::FrontendInitiated
                                           : Service::AM::LaunchType::ApplicationInitiated,
         .program_index = static_cast<s32>(program_index),
+        .previous_program_index =
+            previous_program_id != 0
+                ? static_cast<s32>(previous_program_id -
+                                   FileSys::GetBaseTitleID(previous_program_id))
+                : -1,
     };
 
     m_load_result = m_system.Load(EmulationSession::GetInstance().Window(), filepath, params);
@@ -328,8 +341,12 @@ Core::SystemResultStatus EmulationSession::InitializeEmulation(const std::string
     m_system.GetCpuManager().OnGpuReady();
     m_system.RegisterExitCallback([&] { HaltEmulation(); });
 
+    m_system.RegisterApplicationChangedCallback(
+        [&](u64 changed_program_id) { RequestDiskShaderCacheReload(changed_program_id); });
+
     // Register an ExecuteProgram callback such that Core can execute a sub-program
     m_system.RegisterExecuteProgramCallback([&](std::size_t program_index_) {
+        m_next_program_id = m_system.GetApplicationProcessProgramID();
         m_next_program_index = program_index_;
         EmulationSession::GetInstance().HaltEmulation();
     });
@@ -407,20 +424,58 @@ void EmulationSession::RunEmulation() {
     }
 
     while (true) {
+        std::optional<u64> reload_title;
         {
             [[maybe_unused]] std::unique_lock lock(m_mutex);
-            if (m_cv.wait_for(lock, std::chrono::milliseconds(800),
-                              [&]() { return !m_is_running; })) {
-                // Emulation halted.
-                break;
+            if (m_cv.wait_for(lock, std::chrono::milliseconds(800), [&]() {
+                    return !m_is_running || m_pending_shader_cache_title.has_value();
+                })) {
+                if (!m_is_running) {
+                    break;
+                }
+                reload_title = std::exchange(m_pending_shader_cache_title, std::nullopt);
             }
         }
+
+        if (reload_title.has_value())
+            ReloadDiskShaderCache(*reload_title);
     }
 
     // Reset current applet ID.
     m_applet_id = static_cast<int>(Service::AM::AppletId::Application);
 }
 
+void EmulationSession::RequestDiskShaderCacheReload(u64 program_id) {
+    {
+        std::scoped_lock lock(m_mutex);
+        m_pending_shader_cache_title = program_id;
+    }
+    m_cv.notify_one();
+}
+
+void EmulationSession::ReloadDiskShaderCache(u64 program_id) {
+    if (!Settings::values.use_disk_shader_cache.GetValue())
+        return;
+
+    LOG_INFO(Frontend, "Reloading disk shader cache for {:016X}", program_id);
+
+    const bool was_paused = m_is_paused;
+
+    m_system.Pause();
+    m_system.GPU().WaitForIdle();
+    m_system.GPU().ObtainContext();
+
+    LoadDiskCacheProgress(VideoCore::LoadCallbackStage::Prepare, 0, 0);
+    m_system.Renderer().ReadRasterizer()->LoadDiskResources(program_id, std::stop_token{},
+                                                            LoadDiskCacheProgress);
+    LoadDiskCacheProgress(VideoCore::LoadCallbackStage::Complete, 0, 0);
+
+    m_system.GPU().ReleaseContext();
+
+    if (!was_paused)
+        m_system.Run();
+}
+
 Common::Android::SoftwareKeyboard::AndroidKeyboard* EmulationSession::SoftwareKeyboard() {
     return m_software_keyboard;
 }
diff --git a/src/android/app/src/main/jni/native.h b/src/android/app/src/main/jni/native.h
index 6b171d5a66..5794660bbd 100644
--- a/src/android/app/src/main/jni/native.h
+++ b/src/android/app/src/main/jni/native.h
@@ -4,6 +4,8 @@
 // SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include <optional>
+
 #include <android/native_window_jni.h>
 #include "common/android/applets/software_keyboard.h"
 #include "core/core.h"
@@ -44,6 +46,7 @@ public:
     void HaltEmulation();
     void RunEmulation();
     void ShutdownEmulation();
+    void RequestDiskShaderCacheReload(u64 program_id);
 
     const Core::PerfStatsResults& PerfStats();
     int ShadersBuilding();
@@ -65,6 +68,7 @@ private:
     static void LoadDiskCacheProgress(VideoCore::LoadCallbackStage stage, int progress, int max);
     static void OnEmulationStopped(Core::SystemResultStatus result);
     static void ChangeProgram(std::size_t program_index);
+    void ReloadDiskShaderCache(u64 program_id);
 
 private:
     // Window management
@@ -83,6 +87,7 @@ private:
     Common::Android::SoftwareKeyboard::AndroidKeyboard* m_software_keyboard{};
     std::unique_ptr<FileSys::ManualContentProvider> m_manual_provider;
     int m_applet_id{1};
+    std::optional<u64> m_pending_shader_cache_title;
 
     // GPU driver parameters
     std::shared_ptr<Common::DynamicLibrary> m_vulkan_library;
@@ -93,4 +98,5 @@ private:
 
     // Program index for next boot
     std::atomic<s32> m_next_program_index = -1;
+    std::atomic<u64> m_next_program_id = 0;
 };